Streetcars were the first motor-driven means of public transportation, and they played a key role in the expansion of cities and in improved communications. They were introduced on a large scale in the late 19th century and then went through a period of tremendous growth in the years preceding World War I. In the United States and many other nations they were gradually supplanted after World War I by buses, which can be operated more flexibly, and by underground and elevated railways, which do not contribute to traffic congestion. In some countries, however, streetcars are still in use.
Early History
Motor-driven streetcars were preceded by various types of horse-drawn vehicles. The earliest were omnibuses that operated without tracks. Such vehicles were used in Paris before 1820 and were put into operation in New York about 1830. Later, rails were installed in the streets, and the omnibuses were fitted with wheels that could roll on the tracks. These horsecars gave the passengers a smoother ride and permitted the horses to pull a heavier load. By the end of the 19th century, horsecar systems were used throughout the world.
Early attempts to replace horses with motors met with little success. American inventors in the 1830s and 1840s tried to use electric power, but the wet-cell batteries on which they depended for power were inefficient and expensive. The first successful substitute was the cable car, introduced in San Francisco in 1873 by Andrew S. Hallidie. It received its power from a steam-driven generator, with the cars attached to the moving cable.
Cable cars enjoyed great initial popularity, and lines were installed in several U.S. cities and in some other countries. The disadvantages of these systems -only a single speed was possible, and the cables were frequently damaged or broken, which would tie up an entire route- led to their replacement when efficient electric cars became available.
By the mid-1870s numerous inventors were attempting to utilize the power of the electric generator to run streetcars. A train that was run by power conducted through the tracks was exhibited in Berlin in 1879, and Thomas Edison built a similar vehicle in 1880. Bad weather often caused short circuits in these tracks, and, because they were on the ground, people were exposed to electrical hazards. Other inventors tried, with little success, to harness steam engines and early versions of the internal-combustion engine to streetcars.
Developers soon turned to overhead wires for power transmission. In the United States, Leo Daft and Charles Van Depoele devised slightly different types of trolley cars. Daft's used two overhead wires for an electrical circuit, while Van Depoele employed one wire and one of the tracks to make a complete circuit. The single-wire trolley proved more reliable and was generally adopted. In the mid-1880s their systems were installed in several U.S. cities. Frank J. Sprague, also an American inventor, made several important improvements in trolley-car operations that greatly speeded their public acceptance. His more efficient motors were mounted partly on the axle and partly on the frame, which allowed the car to operate safely over bumps. His first streetcar system, built in Richmond, Va., began running in 1888 and was soon copied by other cities.
